Radical generation enabled by photoinduced N–O bond fragmentation

Abstract

Recent advances in synthetic chemistry have seen a resurgence in the development of methods for visible light-mediated radical generation. Herein, we report the development of a photoactive ester based on...

The Boekelheide Rearrangement of Pyrimidine N‐oxides as a Case Study of Closed or Open Shell Reactions ‐ Experimental and Computational Evidence for the Participation of Radical Intermediates

“…Only the exo ‐methylene intermediate In ‐ 2b shows an absorption reaching the visible part of the spectrum, with a broad band ranging from 320–500 nm (maximum at 385 nm). It is therefore very likely that intermediate In ‐ 2b can be excited by visible light and hence its homolytic cleavage to the radical pair In ‐ 5 / In ‐ 6 (Scheme 7) may be induced [19] …”

“…It is therefore very likely that intermediate In-2b can be excited by visible light and hence its homolytic cleavage to the radical pair In-5/In-6 (Scheme 7) may be induced. [19] Summarizing the experimental facts, it is evident that the mechanistic scenario of the Boekelheide rearrangements of model compound 1 is quite complex. Depending on the conditions, the reaction can occur cleanly affording the expected rearrangement products, e. g., compound 2, essentially without side products.…”

Azolation of Benzylic C–H Bonds via Photoredox-Catalyzed Carbocation Generation

“…Herein we report the implementation of N -alkoxypyridinium salts in this process. Simple N -alkoxypyridinium salts can be readily prepared in one step and offer an electronically tunable HAT scaffold. , Finally, mechanistic evidence suggests that an electron-donor–acceptor (EDA) complex may be operable for activating the pyridinium reagents for certain electron-rich benzylic partners …”

“…Lastly, pyridinium salts have been reported to participate in EDA complexes. ,,, Control experiments suggested that when HFIP is added as a cosolvent, an EDA complex could be operable, on the basis of the observation of product without photocatalyst and an observed bathochromic shift in the UV–vis spectra (Figure b). Presumably, the EDA complex facilitates oxidation of the arene, which triggers fragmentation of pyr-1 to release a methoxy radical.…”

Green light enhanced the photostability and catalytic performance of fatty acid photodecarboxylase

“…Herein, green light illumination under an anaerobic condition efficiently improves the photostability of CvFAP, which will facilitate it as an alternative to organic or inorganic catalysts for decarboxylation reaction. 10,18,[28][29][30][31] However, the conversion of real biowaste with CvFAP still remains very challenging. For instance, when producing sustainable aviation fuels from waste lipids, the matching of lipase and CvFAP activity needs to be considered to avoid acid inhibition to CvFAP.…”